package com.said.today.service.impl;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.said.today.dto.Result;
import com.said.today.entity.Shop;
import com.said.today.mapper.ShopMapper;
import com.said.today.service.IShopService;
import com.said.today.utils.CacheClient;
import com.said.today.utils.RedisConstants;
import com.said.today.utils.RedisData;
import com.said.today.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.TimeUnit;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    // private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
    @Override
    public Result queryById(Long id) {
        // 缓存穿透
        // Shop shop = queryWithThrough(id);
        // Shop shop = cacheClient.queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY, id,
        //         Shop.class, this::getById, RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        // 互斥锁缓存击穿
        // Shop shop = queryWithMutex(id);
        // 逻辑过期解决缓存击穿
        // Shop shop = queryLogicalExpire(id);
        Shop shop = cacheClient.queryLogicalExpire(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);
        if(shop == null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }

    // public Shop queryLogicalExpire(Long id){
    //     String key = RedisConstants.CACHE_SHOP_KEY + id;
    //     // 1.从redis查询商户缓存
    //     String shopJson = stringRedisTemplate.opsForValue().get(key);
    //     // 2.判断是否存在
    //     if(StrUtil.isBlank(shopJson)){
    //         // 3.未命中，直接返回
    //         return null;
    //     }
    //     // 4 命中 先把json反序列化为对象
    //     RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
    //     Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
    //     LocalDateTime expireTime = redisData.getExpireTime();
    //     // 5.判断是否过期
    //     if(expireTime.isAfter(LocalDateTime.now())){
    //         // 6.未过期，直接返回店铺信息
    //         return shop;
    //     }
    //
    //     // 7.已过期，需要缓存重建
    //     String lockKey = RedisConstants.LOCK_SHOP_KEY+id;
    //     boolean lock = tryLock(lockKey);
    //     // 8.判断是否获取到互斥锁
    //     if(lock){
    //         // 9.获取到 开启独立线程进行缓存重建
    //         CACHE_REBUILD_EXECUTOR.submit(()-> {
    //             try {
    //                 // 重建缓存
    //                 this.saveShop2Redis(id,20L);
    //             } catch (InterruptedException e) {
    //                 throw new RuntimeException(e);
    //             } finally{
    //                 // 释放锁
    //                 unlock(lockKey);
    //             }
    //         });
    //     }
    //     // 10.没有获取到互斥锁则直接返回店铺信息
    //     return shop;
    // }

    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        // 1.查询店铺信息
        Shop shop = getById(id);
        Thread.sleep(200);
        // 2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        // 3.写入redis
        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }

    // public Shop queryWithMutex(Long id){
    //     String key = RedisConstants.CACHE_SHOP_KEY + id;
    //     // 1.从redis查询商户缓存
    //     String shopJson = stringRedisTemplate.opsForValue().get(key);
    //     // 2.判断是否存在
    //     if(StrUtil.isNotBlank(shopJson)){
    //         // 3.存在，直接返回
    //         // 反序列化
    //         return JSONUtil.toBean(shopJson, Shop.class);
    //     }
    //     // 判断命中的是否是空值
    //     if (shopJson != null) {
    //         return null;
    //     }
    //     // 4 实现缓存重建
    //     // 4.1获取互斥锁
    //     String lockKey = null;
    //     Shop shop = null;
    //     try {
    //         lockKey = RedisConstants.LOCK_SHOP_KEY + id;
    //         boolean isLockKey = tryLock(lockKey);
    //         // 4.2判断是否获取成功
    //         if(!isLockKey){
    //             // 4.3获取失败，休眠重试
    //             Thread.sleep(50);
    //             return queryWithMutex(id);
    //         }
    //         // 4.4 成功，根据id查询数据库
    //         shop = getById(id);
    //         // 模拟重建的延迟
    //         Thread.sleep(200);
    //         // 5.不存在，返回错误
    //         if (shop == null) {
    //             // 将空值写入redis
    //             stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
    //             return null;
    //         }
    //         // 6.存在，写入redis
    //         stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
    //         // 7.释放互斥锁
    //     } catch (InterruptedException e) {
    //         throw new RuntimeException(e);
    //     } finally {
    //         unlock(lockKey);
    //     }
    //     // 7.返回
    //     return shop;
    // }

    // public Shop queryWithThrough(Long id){
    //     String key = RedisConstants.CACHE_SHOP_KEY + id;
    //     // 1.从redis查询商户缓存
    //     String shopJson = stringRedisTemplate.opsForValue().get(key);
    //     // 2.判断是否存在
    //     if(StrUtil.isNotBlank(shopJson)){
    //         // 3.存在，直接返回
    //         // 反序列化
    //         return JSONUtil.toBean(shopJson, Shop.class);
    //     }
    //     // 判断命中的是否是空值
    //     if (shopJson != null) {
    //         return null;
    //     }
    //     // 4.不存在，根据id查询数据库
    //     Shop shop = getById(id);
    //     // 5.不存在，返回错误
    //     if (shop == null) {
    //         // 将空值写入redis
    //         stringRedisTemplate.opsForValue().set(key,"",RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
    //         return null;
    //     }
    //     // 6.存在，写入redis
    //     stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
    //     // 7.返回
    //     return shop;
    // }

    // private boolean tryLock(String key){
    //     Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
    //     return BooleanUtil.isTrue(flag);
    // }
    //
    // private void unlock(String key){
    //     stringRedisTemplate.delete(key);
    // }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if(id == null){
            return Result.fail("店铺id不能为空");
        }
        // 更新数据库
        updateById(shop);
        // 删除缓存
        stringRedisTemplate.delete(RedisConstants.CACHE_SHOP_KEY+id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 1.判断是否需要根据坐标查询
        if(x == null || y == null){
            // 不需要坐标根据数据库查询
            Page<Shop> page = query()
                    .eq("type_id",typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        // 2.计算分页参数
        int from = (current-1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        // 3.查询redis、按照距离排序、分页。结果：shopId、distance
        String key = RedisConstants.SHOP_GEO_KEY+typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
                key,
                GeoReference.fromCoordinate(x, y),
                new Distance(5000),
                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
        );
        // 4.解析出Id
        if(results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if(list.size() <= from){
            // 没有下一页了，结束
            return Result.ok(Collections.emptyList());
        }
        // 4.1 截取 from -end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            // 4.2获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 4.3获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        // 5.根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id",ids).last("order by field(id,"+idStr+")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        // 6.返回
        return Result.ok(shops);
    }
}
